This sub-project aims to test and develop geological and geochemical vectors to low sulfidation epithermal gold mineralisation in the Cerro Negro district of Argentina by integrating TerraSpec and XRD analyses of clay mineralogy (illite, smectite, kaolinite) with vein textures and, where available, whole rock and mineral geochemistry to help constrain the relative depths of vein segments within discrete fault blocks and proximity to ore.

Francisco Testa and Lejun Zhang conducted fieldwork in February and March 2019 focussed on the Eureka vein system within the district (currently being mined). Hydrothermal alteration mineral zones were detected by means of TerraSpec analyses (e.g., carbonate mineralogy), which aided vectoring towards mineralisation. Based on whole rock geochemistry, both lithologic units (immobile elements) and hydrothermal alteration zones (mobile elements) were detected. Some of the main achievements in the Silica Cap–Gato Salvaje vein systems include: the first documentation of paragenetic sequences, Ar/Ar ages on adularia to date the low sulfidation epithermal event, record textural features, mineralogical zonation, and quartz trace element chemistry, all used as proximity indicators towards mineralised quartz veins. The same analyses were conducted in the Silica Cap lithocap. Some of the major results include first Ar/Ar ages on alunite to date the overprinting advance argillic event, understanding of trace element substitution in HS quartz, which contrasted hydrothermal fluids responsible for the intense silicic alteration exposed on surface, and vector towards heat source, and most importantly provide a genetic model which explains the relationship between low-sulfidation epithermal mineralisation and overprinting lithocap alteration; the latter has proven to be applicable for other areas in the district.

The final report for the project will be provided to Newmont Goldcorp in 2020.

This sub-project commenced in 2018. It is fully funded by new TMVC funder Goldcorp, and aims to test and develop geological and geochemical vectors to low sulfidation epithermal gold mineralisation in the Cerro Negro district of Argentina by integrating Terraspec and XRD analyses of clay mineralogy (illite, smectite, kaolinite) with vein textures and, where available, whole rock and mineral geochemistry to help constrain the relative depths of vein segments within discrete fault blocks and proximity to ore.

Francisco Testa and Lejun Zhang conducted fieldwork in March 2018. Twenty-nine surface samples and 200 drill hole samples were collected for laboratory analysis. TerraSpec measurements were collected from each sample location, and also from surrounding areas and the data were processed by aiSIRIS™.

Two reports were delivered to the project sponsor in 2018.

Geochronology, alteration mineral texture and chemistry studies will be conducted during the first half year of 2019. A second field campaign will be conducted early in 2019.